I played in front of a huge audience at Dreamhack, in their talent show! That room probably had at least 4000 people and their computers. Not all of them were at the stage though, but still.

I was incredibly nervous - I think you can see my hands and my DS shaking in the videos. Screwed up early in the first song, which I'm very annoyed at myself for, but all in all, it went pretty well. I got second place, a nice mousepad, an american flag-patterned one-piece (which I promptly sold), and some great attention.